Cellular wireless networks are increasingly becoming a ubiquitous medium for Internet access. The number of mobile subscribers using mobile Internet services is growing and is expected to continue to grow. As the number of mobile subscribers increases, the requirements for network capacity also increase. Although Third Generation (3G) wireless networks allow high speed data communications, the development and deployment of high-demand data applications and services can quickly exhaust the network capacity and, thus, limit the quality of experience of the mobile subscribers.
In general, wireless service providers have two basic mechanisms for keeping bandwidth demand below available capacity: increase capacity or reduce traffic volume. To increase capacity, wireless service providers can upgrade existing network infrastructure (e.g., by adding more cell towers or deploying new cellular technologies), but this is expensive, time-consuming, and not immediately profitable. To reduce traffic volume, wireless service providers have typically blocked applications that generate large amounts of traffic on the network.
In wireline networks, network-level redundancy elimination has emerged recently as an efficient way to reduce traffic volume on bandwidth-constrained network paths. Redundancy Elimination (RE) algorithms deploy a cache at each end of a network path over which redundant traffic is to be eliminated. At the sending node, for each packet traversing the path, the sending node determines whether any sequences of bytes within the packet are identical to sequences of bytes in packets previously sent via the network path such that the common sequences of bytes in the packet may be signaled using less information than in the common sequences of bytes. At the receiving node, for each packet traversing the path, the receiving node may need to reconstruct the packet where common sequences of bytes have been replaced within the packet. This typically requires at least some level of synchronization between the sending node and the receiving node.
Redundancy elimination has been proposed for use in Wide Area Networks (WANs); however, no attempts have been made to apply redundancy elimination in cellular wireless networks, primarily because the fundamentally different environment of cellular wireless networks complicates deployment of redundancy elimination techniques. First, even though the wireless communication medium is shared, mobile subscribers are aware only of their own packets, and not packets of other mobile subscribers. Second, for efficient redundancy suppression over the air link to the mobile device, redundancy elimination must be deployed at the mobile device, which requires careful tuning of the redundancy elimination techniques to the limited resource of mobile devices. Third, higher loss rates that are common in cellular wireless networks make synchronization of the sender and receiver more complicated.